Detecting HTTP vs. HTTPS

I have an iRule that will definitely be associated with a VS with an HTTP profile but may or may not have a client SSL profile. The rule needs to do a redirect but needs to know whether the client is talking to the BIG-IP via HTTP or HTTPS to know what to use in the redirect URL.

 

 

To me the best way to do this would be to detect whether or not a client SSL profile is associated with the VS -- is there a way to do this? I can't use any of the SSL::* commands, not even in a catch statement, as it can't be applied to a non-HTTPS virtual server in that case.

 

 

Thanks in advance for any help!